The present invention relates to a manufacturing method in a plasma processing apparatus that holds a substrate-like sample such as a semiconductor wafer on a sample stage located in a processing chamber inside a vacuum chamber to process the sample using plasma formed in the processing chamber, and in particular, to a manufacturing method in a plasma processing apparatus which comprises heaters inside a film of a dielectric material on a top surface of the sample stage and which executes plasma processing while adjusting the temperature of the sample through the operation of the heaters.
In recent years, with miniaturized and complicated semiconductor devices, there has been a great demand for batch etching of multilayer films by means of a single etching processing apparatus using plasma, in a preprocess and a postprocess for a semiconductor manufacturing process. In the batch etching, for each film type, etching uniformity needs to be maintained within a wafer surface, and etching shape needs to be appropriately maintained. Each film type has a suitable wafer temperature and radial temperature distribution. Thus, there has been a requirement that every time the film type to be etched is changed, the temperature value and distribution of a sample be quickly and accurately changed.
A proposed technique for implementing this places film-like heaters inside a film composed of a dielectric material and located on a top surface of a sample stage holding a substrate-like sample such as a semiconductor wafer. The technique then executes a process of etching the sample while using the heaters to heat the sample to obtain the desired temperature distribution of the wafer. Advantageously, such a technique using the heaters located adjacent to the sample enables the temperature and temperature distribution of the sample to be quickly changed, and the technique further allows the temperature value to be sufficiently changed even with low heat input from plasma.
A known sample stage containing heaters uses ceramic heaters embedded inside a film of ceramics, which is resistant to heat and corrosion caused by a corrosive gas. As described in JP-UM-A-2-56443, a method for manufacturing such a ceramic heater prepares a ceramic green sheet with a heat resistant film printed thereon in a predetermined shape. The method then laminates a second ceramic green sheet on the first ceramic green sheet to produce a ceramic laminate, and then integrally burns the laminate.
Furthermore, JP-A-7-220862 discloses a method of filling ceramic powder in a mold, performs pressing to form a burned ceramic member having a recess, and arranging heaters in the recess in a predetermined pattern shape; the heaters are each shaped like a coil spring obtained by rolling a wire of a high-melting-point metal. The method then fills the ceramic power into the recess to produce a disc-like compact and subjects the compact to hot pressing. Moreover, JP-A-11-162620 discloses a method of preparing ceramic heaters each made up of a heater electrode embedded in a ceramic base, allowing the heaters to generate heat, measuring the temperature distribution of surfaces of the heaters, and cutting a surface of each of the heaters other than the heating surface which corresponds to a low temperature portion, for example, a back surface, on the basis of the temperature distribution to partly form a thinner portion.
Furthermore, the use of a film obtained by a spray coating method as the dielectric film has hitherto been known; the film is obtained by spraying particles of a material melted at high temperatures using plasma or the like, against a surface of an object. For example, JP-A-6-290917 describes a method of engraving a groove corresponding to a pattern in a surface of a base, forming a lower film, an insulator film, and a heater film by means of spray coating using plasma, and then polishing the base so that the heater film remain inside the groove.